Tire work stand

ABSTRACT

A tire work stand comprises a frame for supporting the work stand on a ground surface and for attaching a set of components to the tire work stand. A plurality of rollers is attached to the frame to support a tire above the ground surface and to permit rotation of a tire during inspection of the tire. A ramp is configured to have a first ramp end capable of extending from the ground surface and a second ramp end extending to a position proximal to the frame. A bridge is configured to have a first bridge end extending from the second ramp end and a second bridge end extending to a position proximal to a surface of at least one of the rollers, wherein the bridge acts to inhibit rotation of the roller during loading of the tire and further permits rotation of the tire after the tire has been loaded on the tire work stand.

FIELD OF THE INVENTION

The present invention relates to the cleaning, inspection, andmaintenance of tires and wheels. Specifically, the present inventionpertains to a tire work stand apparatus for rotating a tire, eithermounted or unmounted, where the loading and unloading of the tire ontoand off the work stand is eased by an automatic roller brake device.

BACKGROUND OF THE INVENTION

A tire work stand, and in particular a portable tire work stand,simplifies inspection of unmounted or mounted tires (especially usefulfor large, heavy truck tires). Tire work stands exist but their designdo not facilitate easy loading and unloading. Portable roller standshaving a typical ramp-style loading system are not satisfactory for usewith a tire that is not attached to a vehicle. For example, US PatentApplication Publication US 2010/020862 shows an apparatus for vehiclewheel maintenance having a pair of spaced apart rollers and a loadingbar such that the rear wheel of a motorcycle can be rolled onto thestand such that the tire rests between the rollers. This allows rotationof the tire. US Patent Application Publication US 2007/0138112 A1discloses a wheel rotation device having a pair of spaced apart rollersand an inclined ramp extending from one of the rollers at a shallowangle to promote loading the tire on the stand.

Upon scrutiny of these devices, however, it should become apparent thatthe dimensions of these devices would not allow them to be useful forinspection of heavy tires, like heavy duty truck tires. In particular,these devices are not satisfactory for use when the tire is not attachedto a vehicle. The usual method of loading/unloading a heavy tireonto/from a portable roller stand is to include a ramped platform thatcan allow the tire to be rolled up/down a small incline whichtransitions between floor level and roller-top level. This method issatisfactory if the tire to to be inspected is mounted on a smallvehicle (such as a motorcycle, for instance) that is being pushed ontothe roller stand. In the case of loading an unmounted tire or tire andwheel assembly onto the tire work stand the force vectors to load thetire are opposite and lead to unsatisfactory performance for a tire notmounted on a vehicle. When the tire is pushed against the roller thetire imposes a force vector on the roller that is in the oppositerotation to the force vector imposed on the roller by the tire of avehicle being pushed. As a result of this difference, a simple ramp issufficient, for example, for a motorcycle roller stand. However, for atire work stand, the force vector in the opposite direction inhibits theability of the tire to rise over the roller and to seat on the standitself

A new type of device having a brake feature on the ramp to preventrotation of the roller overcomes these deficiencies and makes ituniquely suited for use as a tire work stand. The concept would alsowork equally well for applications such as a as a motorcycle rollerstand.

SUMMARY OF THE INVENTION

Aspects and advantages of the invention will be set forth in part in thefollowing description, or may be obvious from the description, or may belearned through practice of the invention.

A tire work stand comprises a frame for supporting the tire work said ona ground surface and for attaching a set of components of the tire workstand. A plurality of rollers is attached to the frame to support a tireabove the ground surface and to permit rotation of the tire duringinspection of the tire. The rollers are rotatable about an axis ofrotation concentric with an axis of the rollers. A ramp is configured tohave a first ramp end capable of extending from the ground surface and asecond ramp end extending to a position proximal to the frame. A bridgeis configured to have a first bridge end extending from the second rampend and a second bridge end extending to a position proximal to asurface of at least one of the rollers, wherein the bridge acts toinhibit rotation of the roller during loading of the tire and furtherpermits rotation of the tire after the tire has been loaded on the tirework stand.

The frame is in frictional contact with the ground surface to aid in thestability of the tire work stand. In one embodiment, the frame comprisesa set of supports mounted to the frame and in frictional contact withthe ground surface and arranged on the frame so as to provide a gapbetween the frame and the ground surface.

The ramp comprises a hinge located on the ramp to permit rotation of theramp such that the first ramp end is movable from a position in contactwith the ground surface to a position away from the ground surface.

A first bridge end of the tire work stand comprises a hinge to permitrotation of the second bridge end from a position in contact with theroller to a position away from the roller. The position of the hingerelative to the frame is adjustable so as to maintain a clearancebetween the tire and the bridge when the tire is in a position forinspection.

In another variation, the first bridge end is rigidly attached to theframe, and the second bridge end extends from the frame to a positionproximal to a surface of at least one of the rollers, and wherein a gapbetween the second bridge end and the roller is maintained when no loadis applied to the ramp.

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the invention and, together with the description, serveto explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appendedfigures, in which:

FIG. 1A is a schematic representation of a tire mounted on a wheel andthe wheel mounted to a vehicle chassis showing the kinematics of thetire being loaded on a tire work stand according to the prior art.

FIG. 1 b is a schematic representation of a tire mounted on a wheel andthe wheel not mounted to a vehicle chassis showing the kinematics of thetire being loaded on a tire work stand according to the prior art.

FIG. 2 is a perspective view of an embodiment of the tire work standaccording to the invention.

FIG. 3 is a side view of a tire loaded onto the tire inspection shown inFIG. 2.

FIG. 4 is an illustration of a tire being loaded onto the tire workstand, depicting the operation of the bridge.

FIG. 5 depicts a tire in the process of loading onto the tire work stand(dashed lines) in relation to a tire loaded onto the tire work stand(solid lines).

FIG. 6 depicts a tire leaded onto the tire work stand with the bridgepositioned in a position for loading or unloading of the tire.

FIG. 7A depicts a tire being loaded onto an additional embodiment of thetire work stand, where the bridge is rigidly attached to the frame.

FIG. 7B depicts a tire loaded onto an additional embodiment of the tirework stand of FIG. 7A, showing the operation of the bridge.

The use of identical or similar reference numerals in different figuresdenotes identical or similar features.

DETAILED DESCRIPTION OF THE INVENTION

A common requirement for the maintenance of tires and tire and wheelassemblies is to perform a visual inspection of the tire for signs ofwear or injury that may make the tire unsuitable for further service. Atire work stand will typically comprise a frame that is comprises a pairof spaced apart and parallel aligned rollers. The rollers allow the tireto freely rotate for inspection. For small tires, it is possible to liftthe tire directly onto the frame so that it rests on the rollers, butfor heavy tires or tire and wheel assemblies, such as those used forheavy duty truck tires, it is not possible to lift the tire withoutassistance from a lifting device such as a hoist. FIG. 1 depicts a tirework stand 15 having a typical ramp-style loading system. When such awork stand is used with a tire mounted on a vehicle, it is easy to loadthe tire onto the stand. In this case the force F to move the tire isapplied from the vehicle frame at the axis of rotation of the tire (i.e.the axle). As the tire leaves the ramp 17 and crosses the roller, theforce continues to urge the tire forward and onto the work stand.

When one attempts to load a tire that is not attached to a vehicle ontoa tire work stand, the forces are very different. In most cases, anoperator will push on the tread of the tire to cause a torque to rotatethe tire and have it ascend the ramp 17 and to approach the roller. Thistorque represented by the dotted arrow on the tire in FIG. 1B. Theroller is configured to freely rotate about its axis. At the momentwhere the tire's contact with the ramp ends and the tire is in contactwith the roller, the torque applied to the tire will now be transferredto the roller, which will freely rotate, as represented by the dottedarrow on the roller in FIG. 1B. The result is that the tire will nolonger move forward to seat between the pair of rollers. The operatormay be forced to try to lift the tire into place.

An embodiment of an improved tire work stand 100 is shown FIG. 2. Thetire work stand 100 comprises a frame for supporting the work stand 100on a ground surface and for attaching a set of components of the tirework stand. A plurality of rollers 120 are attached to the frame tosupport a tire 10 above the ground surface and to permit rotation of atire during work or inspection of the tire 10. To facilitate loading ofthe tire 10 on the tire work stand 100, the stand has a ramp 130 with afirst ramp end 131 capable of extending from the ground surface, and asecond ramp end 132 extending to a position proximal to the frame 110.As used herein, the term “ramp” refers to any means of providing asurface to facilitate rolling the tire onto the work stand. The ramp 130may be linear, curved, or even stepped. The surface of the ramp may besmooth or may also include a friction enhancing surface. Further, thetire work stand 100 has a bridge 140 having a first bridge end 141extending from the portion of the frame 110 proximal to the second rampend 132, and a second bridge end 142 extending to a position proximal tothe surface of at least one of the rollers 120. As used herein, the term“bridge” refers to any means of providing a surface to facilitaterolling the tire onto the work stand 100. The bridge 140 may be linear,curved, or even stepped. The surface of the bridge 140 may be smooth ormay also include a friction enhancing surface. Referring now to FIG. 3and to FIG. 4, when the tire 10 ascends the ramp 130 and the bridge 140,the weight of the tire on the bridge 140 causes the second bridge end142 to contact the surface of the roller 120 and to inhibit rotation ofthe roller 120. See FIG. 4 where the tire 10 shown in solid lines isabout to crest over the roller 120. Since the roller 120 will no longerrotate, the tire 10 will easily mount the roller 120 and reach theloaded position where the tire 10 rests in contact with both rollers120. Referring in particular to FIG. 4, tire 10 is depicted in theloaded position by dotted lines. Once the weight of the tire no longerrests on the second bridge end 142, the roller 120 proximate to it isnow free to rotate. The tire 10 is now free to rotate to facilitateinspection or maintenance.

Referring now to FIG. 5, it can be seen that in the absence of thebridge 140 (as is the case in the prior art), the tire 10 undergoes avertical displacement or lift L between the position where the tire 10is in the crest of roller 120 and the position where the tire 10 isloaded, or rests between the pair of rollers 120. Specifically the axisof tire 10 moves from a position A when loaded to a position A″ whenresting on the crest of the roller 120. During this movement of the axisit the tire 10, the roller 120 is free to rotate and increases thedifficulty to unload the tire 10 from the work stand 100. In the loadedposition, the position A is a vertical distance equal to h₀ above a linepassing through the axes of rotation of the rollers 120. In theunloading position, the position A″ is a vertical distance (R_(T)+R_(R))above a line passing through the axes of rotation of the rollers 120.The lift L may be determined from the dimensions of the work stand 100and from the dimension of the tire 10:

L=(R _(T) +R _(R))−h ₀ and h ₀ ²=(R _(T) +R _(R))²−(W/2)²

where:

-   -   R_(T)=radius of the tire 10    -   R_(R)=radius of the roller 120    -   W=spacing between the rollers 120 as mounted on the frame 110

For the ease of loading of the tire, and more importantly, for the easeof unloading the tire, the lift L should be minimized. For a work standas known in the prior art, the tire will undergo the full lift L duringloading and unloading. To accomplish this, the tire must be rotatedthrough and angle α₀ defined (and illustrated in FIG. 4) as the anglemeasure from the 12 o'clock position on the roller 120 and a pointlocated at the point of contact between the tire 10 and the roller 120.For the tire work stand of the prior art, the angle α₀ may be determinedas:

α₀=sin⁻¹ [W/(2·(R _(T) +R _(R))]

For a tire work stand 100 that is dimensionally sized to accommodate atypical heavy truck the of size 275/80R22.5, the tire 10 will have adiameter of about 1018 mm (R_(T)=509 mm) and the roller 120 will have adiameter of about 50 mm (R_(R)=25 mm), spaced apart about by a distanceW=400 mm. Applying these date to the equations above obtains the a valueof L≈495 mm, a value of h₀≈39 mm and a value of α₀≈22 degrees.

Turning now to FIG. 6, it can be appreciated that the roller 120 will beinhibited from turning as soon as the tire 10 contacts the second bridgeend 142. That is to say, the axis of tire 10 moves from a position Awhen loaded to a position B when the tire 10 contacts the second bridgeend 142. In this interval between the position A and the position B, thetire 10 now undergoes a rotation angle α₁ which is much less than α₀.The reduction of this angle facilitates easy removal of the tire 10 fromthe work stand 100. The clearance between the second bridge end 142 andthe tire can be made small or near zero. In that case, a small rotationof the tire 10 will cause it to immediately contact the second bridgeend 142 and inhibit the rotation of the roller 120. For practical designconsiderations and to accommodate tires of different diameter, it isadvantageous to maintain a small clearance between the tire 10 (whenloaded) and the second bridge end 142. This is illustrated in FIG. 6where the second bridge end 142 ends just clear of the tread of the tire10. To further accommodate multiple tire sizes, the position of thehinge relative to the frame can be made adjustable so as to maintain aclearance between the tire and the bridge when the tire is in a positionfor inspection.

Referring again to FIG. 6, an embodiment of the tire work stand 100 isshown where the ramp 130 is rotatable to permit rotation of the ramp 130such that the first ramp end 131 moves from a position in contact withthe ground surface to a position away from the ground surface. It can beappreciated from FIG. 6 that when the ramp 130 is rotated to its fullclockwise position, then the tire work stand 100 becomes more compactfor storage or transportation. In this non-limiting example as shown inFIG. 6, the hinge 150 as a simple gate hinge. However, it is within thescope of the invention for the hinge 150 to be any means that providessuitable freedom of rotation of the ramp 130. The hinge 150 is attachedto the frame 110 by means of bolts and nuts. However, the hinge 150 maybe attached to the frame 110 by any suitable means such as welding,bonding, or may be fabricated as an integral part of the frame 110.

FIG. 6 also depicts an additional detail of the tire work stand 100where the bridge 140 is rotatable to permit rotation of the bridge 140such that the second bridge end 142 moves from a position proximal to orin contact with the roller 120 to a position away from the roller. Ahinge 150 located on the second ramp end 132 to permit such rotation.FIG. 3 depicts the work stand 100 with the bridge 140 in thecounterclockwise rotated position. It can be seen that this movement ofthe bridge 140 ensures that it will not interfere with the rotation ofthe roller 120 as the tire 10 is rotated during inspection ormaintenance. In this non-limiting example as shown in FIG. 6, the hinge150 is a simple gate hinge. However, it is within the scope of theinvention for the hinge 150 to be any means that provides suitablefreedom of rotation of the bridge 140. The hinge 150 is attached to theframe 110 by means of bolts and nuts. However, the hinge 150 may beattached to the frame 110 by any suitable means such as welding,bonding, or may be fabricated as an integral part of the frame 110.

Referring now to FIG. 7 a and 7B, an alternative embodiment is shownwhere the bridge 145 is rigidly attached to the frame and the secondbridge end 147 extends from the frame to a position proximal to asurface of at least one of the rollers. In this embodiment, the bridgeacts as a spring member to maintain a gap C between the second bridgeend 147 and the roller 120 when no load is applied to the bridge. Thesize of the gap C is not critical, but should be at least 2-3 mm tounsure that the tire 10 and roller 120 are free to rotate duringinspection or maintenance of the tire 10. During the operation ofloading of the tire 10, the force applied to the bridge 145 by theweight of the tire 10 will cause the second bridge end 147 to contactthe roller 120 and to inhibit rotation of the roller 120. Thisembodiment maintains the ramp 130 that is rotatable.

In still another embodiment (not shown), the ramp 130 and the bridge 145may comprise a unitary component which may be rigidly attached to theframe 110 as for the bridge 145 depicted in FIGS. 7A and 7B. The ramp130 and the bridge 145 are a single unit. This unit may be maderemovable from the frame 110 by means of tabs and slots or any means toprovide positive location of the unit on the frame 110. Thus theadvantages of ease of use and portability are maintained.

The dimensions of the tire work stand 100 may be specified toaccommodate different sizes and types of tires. For example, the axiallength of the rollers, and hence, the width of the frame 110, would bespecified according to the tread width of the tire 10. For theembodiments shown in the attached Figures, the rollers 120 have acylindrical shape and the radius R_(R) of the rollers is constant alongan axial length of the rollers 120. However, if the tire 10 has a veryround cross-section to its tread, as often found on motorcycle tires,then the rollers 120 may have cylindrical shape and a radius of therollers is variable along an axial length of the rollers. For amotorcycle tire, it may be advantageous to have the minimum radius inthe center of that length of the roller 120 to urge the tire toself-center on the rollers 120. The rollers 120 used for a prototypetire work stand 100 are of a ball bearing construction and have adiameter between 40 mm and 60 mm. The diameter may be varied; forexample, increased to obtain higher load capacity for larger tires.

To solidly locate the tire work stand 100 on the ground surface, it willbe advantageous for a bottom surface of the frame to be in frictionalcontact with the ground surface. To accomplish this, a set of supports115 may be mounted to the frame 110 and in frictional contact with theground surface and arranged on the frame 110 so as to provide a gapbetween the frame and the ground surface.

The longitudinal length of the tire work stand 100 is determined by therange of tire diameters for which the work stand 100 will be used, aswell as the need to maintain a gap between the frame and the groundsurface. It is apparent from FIG. 5 that the distance from the groundsurface to the axis of rotation of the tire A must be greater than thedistance h₀ shown in FIG. 5 and which may be calculated from thefollowing equation:

h ₀ ²=(R _(T) +R _(R))²−(W/2)²

where:

-   -   RT=radius of the tire 10    -   RR=radius of the roller 120    -   W=spacing between the rollers 120 as mounted on the frame 110

The gap between the ground surface may be altered by changing the heightabove the ground at which the rollers 120 are mounted or by altering thevertical dimension of the supports 115. The tire work stand 100 may morereadily accept different sizes of tires when the frame 110 is adjustableto vary the length W between the axes of rotation of the rollers 120(not shown). For the example tire 10 of size 275/80R22.5, thelongitudinal distance W between the axes of rotation of the rollers 120is about 400 mm. This dimension has been found to work effectively for arange of tire sizes that includes motorcycle tires through smallearthmover tires. The important element is that the tire 10 does notinterfere with the bridge 140 when the tire 10 is loaded onto the tirework stand 100. This can be avoided with either by adjusting the spacingW between the rollers 120 or adjusting the position of second bridge and142 relative to the roller 120. The frame 110 can be made adjustable bya variety of means. For example, the elements of the frame 110 can bemade telescopic to allow adjustability.

While the present subject matter has been described in detail withrespect to specific embodiments and methods thereof, it will beappreciated that those skilled in the art, upon attaining anunderstanding of the foregoing may readily produce alterations to,variations of, and equivalents to such embodiments. Accordingly, thescope of the present disclosure is by way of example rather than by wayof limitation, and the subject disclosure does not preclude inclusion ofsuch modifications, variations and/or additions to the present subjectmatter as would be readily apparent to one of ordinary skill in the art.

1. A tire work stand comprising; a frame for supporting the tire workstand on a ground surface and for attaching a set of components to thetire work stand; a plurality of rollers attached to the frame to supporta tire above the ground surface and to permit rotation of the tireduring inspection of the tire, the rollers being rotatable about an axisof rotation concentric with an axis of the rollers; a ramp having afirst ramp end capable of extending from the ground surface and a secondramp end extending to a position proximal to the frame, and a bridgehaving a first bridge end extending from the second ramp end and asecond bridge end extending to a position proximal to a surface of atleast one of the rollers, wherein the bridge acts to inhibit rotation ofthe roller during loading of the tire and further permits rotation ofthe tire after the tire has been loaded on the tire work stand.
 2. Thetire work stand according to claim 1, wherein a bottom surface of theframe is in frictional contact with the ground surface.
 3. The tire workstand according to claim 2, further comprising a set of supports mountedto the frame and in frictional contact with the ground surface andarranged on the frame so as to provide a gap between the frame and theground surface.
 4. The tire work stand according to claim 1, wherein thesecond bridge end is positioned relative to the tire to maintain aclearance between the tire and the bridge when the tire is in a positionfor inspection.
 5. The tire work stand according to claim 1, wherein thefirst bridge end further comprises a hinge to permit rotation of thesecond bridge end from a position in contact with the roller to aposition away from the roller.
 6. The tire work stand according to claim5, wherein the position of the hinge relative to the frame is adjustableso as to maintain a clearance between the tire and the bridge when thetire is in a position for inspection.
 7. The tire work stand accordingto claim 1, wherein the ramp further comprises a hinge located at thesecond ramp end and the ramp is rotatable about an axis of the hingesuch that the first ramp end is movable from a position in contact withthe ground surface to a position away from the ground surface.
 8. Thetire work stand according to claim 1, wherein the bridge is rigidlyattached to the frame and the bridge extends from the frame to aposition proximal to a surface of at least one of the rollers, andwherein a gap between the second bridge end and the roller is maintainedwhen no load is applied to the bridge.
 9. The tire work stand accordingto claim 6, wherein the bridge and the ramp comprise a unitarycomponent.
 10. The tire work stand according to claim 1, wherein therollers have a cylindrical shape and a radius of the rollers is constantalong an axial length of the rollers.
 11. The tire work stand accordingto claim 1, wherein the rollers have a cylindrical shape and a radius ofthe rollers is variable along an axial length of the rollers.
 12. Thetire work stand according to claim 1, wherein the rollers have adiameter between 40 mm and 60 mm.
 13. The tire Work stand according toclaim 1, wherein the frame is adjustable to vary the length between theaxes of rotation of the rollers.
 14. A tire work stand comprising; aframe for supporting a tire work stand on a ground surface and forattaching a set of components to the tire work stand; a plurality ofrollers attached to the frame to support a tire above the ground surfaceand to permit rotation of the tire during inspection of the tire, therollers being rotatable about an axis of rotation concentric with anaxis of the rollers; a ramp having a first ramp end capable of extendingfrom the ground surface and a second ramp end extending to a positionproximal to the frame; a bridge having a first bridge end extending fromthe second ramp end and a second bridge end extending to a positionproximal to a surface of at least one of the rollers, wherein the bridgeacts to inhibit rotation of the roller during loading of the tire andfurther permits rotation of the tire after the tire has been loaded onthe tire work stand; wherein the first bridge end comprises a hinge topermit rotation of the second bridge end from a position in contact withthe roller to a position away from the roller, and; wherein the secondramp end further comprises a hinge located on the ramp to permitrotation of the ramp such that the first ramp end moves from a positionin contact with the ground surface to a position away from the groundsurface.
 15. A tire work stand according to claim 14, wherein the secondbridge end is positioned relative to the tire to maintain a clearancebetween the tire and the bridge when the tire is in a position forinspection.
 16. A tire work stand comprising; a frame for supporting atire work stand on a ground surface and for attaching a set ofcomponents to the tire work stand; a plurality of rollers attached tothe frame to support a tire above the ground surface and to permitrotation of a tire during inspection of the tire, the rollers beingrotatable about an axis of rotation concentric with an axis of therollers; a ramp having a first ramp end capable of extending from theground surface and a second ramp end extending to a position proximal tothe frame; a bridge having a first bridge end extending from the secondramp end and a second bridge end extending to a position proximal to asurface of at least one of the rollers, wherein the bridge acts toinhibit rotation of the roller during loading of the tire and furtherpermits rotation of the tire after the tire has been loaded on the tirework stand; and wherein the position of the hinge relative to the frameis adjustable so as to maintain a clearance between the tire and thebridge when the tire is in a position for inspection.